Metal tubing



Dec. 11, 1928. v 1,694,962

E'. R. BERRY METAL TUBING Filed June 6 1923 [/7 Men 6 0/; EdwardRBe/v'y,

Wis .flttorney.

Patented Dec. 11, 1928.

UNITED STATES PATENT OFFICE.

EDWARD 1R. BERRY, OF MALDEN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

METAL Application filed June 6,

The present invention relates to the manufacture of metal tubing.

It is the object of my invention to provide a convenient method ofmaking metal 5 tubes which are seamless and may be made extremelythin-walled if so desired.

In accordance therewith the desired metal, for example, copper, isdeposited upon a core of silica, or quartz, from which the resultingtube may be removed when expanded thermally or otherwise. As moderateheating causes much greater expansion of the metal than of the silicacore it furnishes a convenient method of rendering the shell and coreseparable.

The accompanying drawings illustrate the steps of carrying out myinvention, Fig. 1 illustrating the core or mandrel before deposition ofthe metal; Fig. 2 the core coated preliminary to the electrolysis withconducting material; Figs. 3 and 4 show the deposit built up byelectrolysis; and Fig. 5 illustrates the finished article.

The mandrel or core 1, consisting of fused quartz and having a smoothsurface, first is provided with a conductive base 2 (Fig. 2) consistingfor example, of a thin film of silver which may be deposited on the coreby one of the processes used in the manufacture of mirrors.

Copper or other desired metal is deposited by electrolysis on the base 2to desired thick ness, as shown in Fig. 3. The finished tube 3 finallyis removed from the core at a temperature of about 300 C., or the metalmay be mechanically expanded by burnishing, which allows the tube to beeasily removed from the mandrel. Due to the great difference in thermalcoefiicient of expansion of TUBING.

1923. Serial N0. 643,786.

quartz and metals, such as copper or silver, the core is easilyremovable from the shell. Although the drawing shows a cylindrical tubeof uniform diameter, the invention obviously is not limited to themanufacture of tubes of this particular shape.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

l The method of making metal tubing which consists in electro-depositingthe desired metal on a silica support and removing said support at asufliciently high temperature to cause separation of said members due todifference in thermal expansion.

2. A mandrel constituted of vitreous silica for the fabrication of metaltubing by depo-- sition of metal thereon.

3. The method of making metal tubing which comprises electroplatingmetal onto a support having a coeflicient of expansion which is lowcompared with the coeflicient of expansion of the deposited metal, andheating the combined support and deposited metal to a temperaturesufliciently high to permit, separation. of the holder and depositedmetal.

4. The method of making metal tubing which comprises applying a metallicfilm to a non-conducting support having a' coefficient of expansionwhich is low compared with the co-efiicient of expansion of saidmetallic film, electro-depositing metal onto said film, and heating thecombined support and metal to a temperature sufficiently high to permitseparation of the support and deposited metal.

In witness whereof I have hereunto set my hand this first da of June,1923.

DWARD R'BERRY.

